The present invention relates to head up display systems and projection units used therein, for use in vehicular applications, and the like.
The assignee of the present invention manufactures head up display systems for use in vehicles. Heretofore, head up display systems have been specifically designed for use in each respective vehicle, with optics custom designed for the specific application. It would be desirable to have a head up display system that is modular and permits different optical designs and display devices without changing the complete system. It would also be desirable to have a head up display system that that has a improved projection unit incorporating improved backlight and display devices, and incorporates cooling apparatus.
The present invention provides for a head up display system that may be advantageously used in automotive and other vehicular applications. The present system has a projection unit that is a subassembly by itself. The projection unit comprises a backlight, a display, and cooling apparatus. If required, electronics, mirrors, reflectors, polarizers, diffusers, and the like, may also be enclosed within the projection unit. Different display types require different components. A single image source or multiple image sources may be used within the projection unit. A reduced-to-practice embodiment of the head up display system was built using dual image sources.
An exemplary head up display system comprises a housing, an aspheric reflector, and a modular projection unit. The modular projection unit comprises one or more image sources including a backlight, a spherical reflector, an infrared mirror, a display device, and cooling apparatus for cooling the projection unit.